Regionalizing global models:

Transcription

1 Regionalizing global models: value-adding for impacts and adaptation Jason Evans University of New South Wales Yann Arthus-Bertrand / Altitude

2 Regionalizing Global models Why would we want to regionalize (or downscale) global climate projections? How can we downscale climate projections? What do global models predict for Australia or Sydney? What downscaled climate projection data is available? What downscaled climate projection is coming soon?

3 Why would we want to regionalize (or downscale) global climate projections?

4 Global model simulations

5 Global model simulations

6 Global to Regional Precipitation Global Model Regional Model

7 Global model simulations

8 Global model simulations

9 Global to Regional Temperature Global Model Regional Model

10 For Impacts and Adaptations Often local or regional in nature Often sensitive to extremes (which are regional/local in nature) Management decisions often made locally So Information provided should be locally relevant and preferably application ready Impacts and adaptation will be directly addressed in the IPCC Working Group II report due April 2014

11 How can we downscale climate projections?

12 Methods for providing regional climate projections Scaling Alter past observations based on changes in global models Assumes the future looks like some multiple of the past Needs long time series of observations Easy to calculate Statistical Downscaling Find a statistical relationship between climate produced by a global model and station data. Use this relationship to downscale the global model projection Assumes that this statistical relationship does not change in the future Needs long time series of observations Does not require a lot of computing power Dynamical Downscaling Apply mathematical model of climate system at higher resolution Assumes that the physical laws of nature do not change in the future Solves for all climate variables Requires a lot of computing power

13 What do global models predict for Australia or NSW?

14 Mean temperature change by end of 21 st century CMIP5 models RCP4.5 RCP8.5

15 Mean temperature change by end of 21 st century CMIP5 models CMIP3 models A1B RCP4.5 A2 RCP8.5

16 Mean temperature change by end of 21 st century CMIP5 models CMIP3 models Climate Change in Australia CMIP3 A1B RCP4.5 A2 RCP8.5

17 Mean precipitation Change at end of 21 st century CMIP5 Models RCP8.5 DJF MAM JJA SON

18 Mean precipitation Change at end of 21 st century CMIP5 Models RCP8.5 CMIP3 Models A1B DJF MAM JJA SON

19 Mean precipitation Change at end of 21 st century CMIP5 Models RCP8.5 CMIP3 Models A1B Climate Change in Australia CMIP3 (High emission) DJF DJF MAM MAM JJA JJA SON SON

20 What regional (downscaled) climate projections are already available for NSW?

21 Some available regional climate data Scaling approaches High resolution climate projections produced Australia-wide using a scaling approach based on CMIP3 models, by former QCCCE for DAFF. Available here High resolution climate projections produced in SEACI using a scaling approach for south-east Australia based on CMIP3 models. Statistical Downscaling Many people have produced their own statistical model for downscaling to their stations of choice. One analogue statistical technique developed at BoM has been applied Australiawide (Bertrand Timbals group). Availability? Dynamical Downscaling Climate Futures for Tasmania. CSIRO downscaled with the CCAM model. Available here

22 What regional (downscaled) climate projections are being prepared for NSW?

23 NARCliM NSW/ACT Regional Climate Modelling project NARCliM is being developed by the NSW Office of Environment and Heritage, in collaboration with the Climate Change Research Centre at the University of NSW. NARCliM is delivering regional climate projections at 10km resolution across NSW & ACT by the end of 2014 (50km resolution over Australia) 4 CMIP3 GCMs are being downscaled by 3 RCMs to produce a 12 member ensemble Three 20 year periods are being simulated: , , Uses the SRES A2 emission scenario The data will be made available through a web portal

24 CORDEX COordinated Regional climate Downscaling EXperiment A World Climate Research Programme (WCRP) effort focused on regional climate modelling and downscaling (RCD A regional climate companion to the CMIP5 GCM experiments. Develop a framework to evaluate and possibly improve RCD techniques for use in downscaling global climate projections. Foster an international coordinated effort to produce improved multi-model RCD-based high resolution climate change information over regions worldwide for input to impact/adaptation work and to the IPCC 5th Assessment Report (AR5). Promote greater interaction and communication between global climate modellers, the downscaling community and end-users to better support impact/adaptation activities. Standard resolution 50km Data will start to become available in 2014 and increase over next several years

25 CORDEX Domains

26 CORDEX AustralAsia Domain

27 Further Information Yann Arthus-Bertrand / Altitude